Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
  • G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
  • G01D5/2013—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils by a movable ferromagnetic element, e.g. a core
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
  • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
  • F16C32/00—Bearings not otherwise provided for
  • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
  • F16C32/0406—Magnetic bearings
  • F16C32/044—Active magnetic bearings
  • F16C32/0444—Details of devices to control the actuation of the electromagnets
  • F16C32/0446—Determination of the actual position of the moving member, e.g. details of sensors
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
  • G01D5/2006—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils
  • G01D5/202—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the self-induction of one or more coils by movable a non-ferromagnetic conductive element
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
  • G01D5/204—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01D—MEASURING NOT SPECIALLY ADAPTED FOR A SPECIFIC VARIABLE; ARRANGEMENTS FOR MEASURING TWO OR MORE VARIABLES NOT COVERED IN A SINGLE OTHER SUBCLASS; TARIFF METERING APPARATUS; MEASURING OR TESTING NOT OTHERWISE PROVIDED FOR
  • G01D5/00—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable
  • G01D5/12—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means
  • G01D5/14—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage
  • G01D5/20—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature
  • G01D5/204—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils
  • G01D5/2046—Mechanical means for transferring the output of a sensing member; Means for converting the output of a sensing member to another variable where the form or nature of the sensing member does not constrain the means for converting; Transducers not specially adapted for a specific variable using electric or magnetic means influencing the magnitude of a current or voltage by varying inductance, e.g. by a movable armature by influencing the mutual induction between two or more coils by a movable ferromagnetic element, e.g. a core

Definitions

• US 9,470,505 discloses another contactless electromagnetic sensor for determining the angular position of a rotor. Coils are arranged relative to the rotation axis so that signals are generated that vary sinusoidally with the angular position of the rotor. Also this sensor is unsuitable for determining a radial position of the rotor.
• a contactless electromagnetic sensor for determining a radial position of a rotor configured for rotation about a longitudinal axis.
• the sensor comprises: a first transducer comprising one or more first coils;
• processing circuitry for receiving transducer signals from the first transducer (in particular, directly or indirectly from the first coils), and for deriving at least one position signal indicative of a radial position of the rotor based on the transducer signals,
• the resulting disturbance signal is a convolution of the angular distribution of the defects with the angular sensitivity distribution of the coils.
• the resulting disturbance signal is sinusoidal and rotor- synchronous, having the same form as an unbalance signal.
• the disturbance signal can therefore be easily compensated very much like an unbalance signal. Specifically, in the context of active magnetic bearing devices, such compensation can be carried out without negative impact on the control of the magnetic bearings.
• a radial position sensor comprising a transducer that has sinusoidal response behavior with respect to deviations of the target from perfect rotational symmetry, it becomes possible to more easily compensate for the disturbance signals resulting from such deviations.
• each first coil can comprise a plurality of differently sized, overlapping conductor loops, and the conductor loops can be arranged so as to result in a sinusoidal sensitivity distribution of said coil.
• Suitable arrangements of the conductor loops can easily be derived from numerical simulations of the field generated by an AC current through the conductor loops and of the resulting induced voltages, as will be discussed in more detail below in conjunction with Figs. 10- 13.
• the transducer can further comprise one or more (in particular, two) third coils, wherein the third coils also have sinusoidal sensitivity to a target material along the circumferential direction, and wherein the sensitivity of the third coils varies with the same periodicity as the sensitivity distribution of the first and second coils, but is shifted relative to the latter along the circumferential direction, i.e., the sensitivity distribution of the third coils has a different phase (direction) than the sensitivity distribution of the first and second coils.
• the second transducer can further comprise one or more (in particular, two) second coils that also have a sensitivity to the presence of a target material that varies sinusoidally along a circumferential direction, the sensitivity distribution of the second coils having the same periodicity as the sensitivity distribution of the first coils of the second transducer, but shifted relative to the sensitivity distribution of said first coils along the circumferential direction, preferably by the same amount as in the first transducer.
• the second transducer can be arranged immediately axially adjacent to the first transducer, and the first and second transducers can be axially separated by an electrically conducting shielding member, the shielding member preferably being ring-shaped.
• the second transducer may be configured to determine an angular (rotary) position of the rotor about the longitudinal axis.
• the coils of the second transducer may be configured to couple with a second target portion of the rotor, the second target portion being rotationally asymmetric (eccentric), and the processing circuitry may be configured to receive transducer signals from the first and second transducers and to determine position signals indicative of at least one radial position and an angular position of the rotor based on the transducer signals, in particular, by correlating the transducer signals of the first and second transducers.
• the reference target is a ring arranged in a fixed spatial relationship to the coils of the second transducer. Depending on whether the rotor is an internal or external rotor, the reference target may be arranged on an inner or outer circumference of the second transducer.
• the present invention provides a transducer that is specifically adapted to be employed in a contactless electromagnetic radial position sensor as described above.
• the transducer comprises:
• annular coil support the annular coil support defining a longitudinal axis; and one or more (in particular, two) first coils mounted on the annular coil support.
• the annular coil support may define a plurality of slots that are open towards an inner or outer circumference of the annular coil support, the first and second coils being formed by wires that are received in the slots.
• the coil support is produced by 3D printing. 3D printing is advantageous as it minimizes tooling costs and at the same time permits the creation of complicated structures such as the slots required to accommodate the wires of the coils.
• the coil support can be produced by more traditional methods, like injection molding.
• the present invention provides a method of determining a position of a rotor, in particular, a radial position, the method comprising:
• a rotor for rotation about a longitudinal axis, the rotor comprising a target portion
• a transducer comprising one or more coils that have a sensitivity that varies sinusoidally along a circumferential direction, the coils being arranged to couple with the target portion of the rotor,
• the method can be carried out with the sensor of the first aspect of the present invention.
• the transducer can be the transducer of the second aspect of the present invention, and all considerations discussed in conjunction with the first and second aspects also apply to the method of the third aspect.
• Fig. 1 shows, in a perspective view, a transducer assembly for an eddy-current position sensor according to a first embodiment of the present invention
• Fig. 2 shows the transducer assembly of Fig. 1 in a plan view
• Fig. 3 shows the transducer assembly of Fig. 1 in a side view
• Figs. 6-9 show four different coil support segments of the transducer assembly of Fig.
• Fig. 1 1 shows a highly schematic sketch illustrating the arrangement of first and second coils on a coil support
• Fig. 12 shows a diagram illustrating the flux densities generated by two overlapping coils as a function of angular position when identical DC currents are fed through both coils; circles and crosses indicate the positions of the turns of each coil, and solid and broken lines indicate flux density generated by each coil;
• Fig. 13 shows a diagram illustrating the voltage contributions induced in each of the overlapping coils as a result of the time-dependent local flux that is generated at each angular position when identical AC currents are fed through both coils;
• Fig. 14 shows a diagram illustrating the resulting sensitivity distribution over the entire angular range from 0° to 360°;
• Fig. 15 shows a schematic sketch illustrating a sensor that is capable of determining both a radial position along the x axis and an angular position
• Fig. 16 shows, in a perspective view, a transducer assembly according to a second embodiment of the present invention
• Fig. 17 shows a schematic sketch illustrating a sensor that is capable of determining both a radial position along the x axis and the diameter of the target;
• Fig. 19 shows a schematic sketch illustrating a flexible printed circuit board carrying two coils for a transducer assembly according to a fourth embodiment of the present invention.
• a transducer assembly 1 according to a first embodiment of the present invention is illustrated in Figures 1-5.
• the transducer assembly 1 is configured to determine the radial position of a hollow external rotor (not illustrated in Figs. 1-5) that radially surrounds the transducer assembly 1. Accordingly, the transducer assembly 1 is configured to interact with target surfaces on the inner circumference of the hollow rotor.
• the transducer assembly 1 comprises a first transducer 100 and a second transducer 100’.
• Each transducer 100, 100’ comprises an annular coil support 110, 1 10’.
• the annular coil supports 110, 110’ define a common longitudinal axis L (Fig. 3).
• the transducer assembly 1 comprises an electrically conducting annular bottom plate 120.
• the transducers 100, 100’ are separated by an electrically conducting shielding ring 130.
• the transducer assembly comprises an electrically conducting annular top plate 140.
• a connector board 160 in the form of a rigid printed circuit board (PCB) is disposed, which carries a standard connector 161 for connecting the transducer assembly 1 to excitation and processing circuitry.
• the various parts of the transducer assembly 1 are held together by a plurality of screws 150 extending parallel to the longitudinal axis L.
• Each coil support 110, 110’ carries two first coils and two second coils (not shown in Figs. 1-5), which will be explained in more detail in conjunction with Figs. 10 and 11.
• Each coil consists of several loops of an insulated conducting wire (e.g., coated copper wire).
• Each coil support 1 10, 1 10’ is composed of sixteen coil support segments.
• Figures 6 and 7 illustrate two types of coil support segments 111, 112. Only these two types of coil support segments are required to assemble the first coil support 110.
• Each coil support segment 111, 112 extends over an angular range of 45° and carries an arrangement of slots 113 for receiving the wires of the coils, as well as one- and two-sided hook elements 114, 115 for deflecting the wires into loops and for holding the loops in place.
• Connecting slots 116 serve to connect the coils to connector 161.
• Each segment 111, 112 is provided with two holding lugs 117 disposed at an angular distance of 22.5° for mounting the segment to an axially adjacent segment, to the shielding ring 130 and to the bottom and top plates 120, 140.
• Each segment 111 of the first type forms a pair with a segment 112 of the second type, these segments being mirror-symmetric about a radial plane and being placed side by side along the longitudinal axis L.
• Two pairs, arranged mirror-symmetrically with respect to an axial plane, form a 90° sector of the coil support.
• the coil support is composed of four such identical sectors.
• FIG. 11 Two further coil support segments 11 G, 112’, which are slight variants of the coil support segments 111, 112 of Figs. 6 and 7, are illustrated in Figs 8 and 9.
• the layout of the slots 1 13 and hook elements 114, 115 is the same as in the coil support segments 111, 112, and therefore the coil support segment 1 1 G can be considered to be of the same type as the coil support segment 111, and the coil support segment 112’ can be considered to be of the same type as the coil support segment 112.
• the coil support segments 111’, 1 12’ carry holding lugs 117’ that are thinner with respect to the axial direction than the holding lugs 117 of the coil support segments 111, 112. As apparent from Fig.
• each coil support segment 111, 112’ is used at one axial end of the second transducer 110’ so as to accommodate the connector board 160 between the holding lugs 117’ and the top plate 140.
• Each coil support segment 111, 111 % 112, 112’ is made of an electrically insulating material. It can readily be manufactured by 3D printing or injection molding.
• the bottom plate 120, the shielding ring 130, and the top plate 140 act as electromagnetic shielding members to shield the transducers 100, 100’ from each other and from further components disposed axially adjacent to the transducer assembly. They are preferably made of a metal, in particular, aluminum.
• Each of the first and second coils carried by the coil supports 110, 110’ comprise a plurality of loops, the loops having increasing length along the circumferential direction.
• the loops are all parallel to the cylindrical outer surface of the coil supports 110, 110’, which thus defines a common curved coil surface which defines a set of normal vectors N facing radially outside.
• the arrangement of the loops is schematically illustrated for one coil 170 in Fig. 10.
• the center of coil 170 is assumed to be at angular position 0°. In the present example, nine loops are present.
• the innermost first loop extends over an angular range from—11.5° to +11.5°
• the second loop over an angular range from—23° to +23°
• the third loop from—35.75° to +35.75°, and so on.
• the turning positions (positions of inflection) of each loop are located at plus and minus the following angular positions: 11.5°, 23°, 35.75°, 47.25°, 54.25°, 67°, 72.75°, 82.5°, and 85.5°.
• the turning positions will generally be at different angular positions.
• the coil support has a hook element for forcing the wire of the coil into a 180° turn.
• Fig. 10 the loops are depicted as having different widths along the axial direction. However, in practice all loops will have essentially the same width, the wires of the loops being placed on top of each other or directly adjacent to each other in those loop portions that extend along the circumferential direction.
• Each transducer 100, 100’ comprises two first coils 170, 172 arranged at an angular distance of 180°, the centers of these two coils being at positions 0° and 180°, and two identical second coils 171, 173, which are shifted with respect to the first coils by 90°, having their centers at 90° and 270°, and which overlap with the first coils.
• the loops of all coils 170-173 are arranged in or parallel to the cylindrical outer circumferential surface of the coil support 110, facing radially outside.
• Fig. 12 This figure shows the dependence of flux density as a function of angular position for one of the first coils (designated as coil A) having its center at 0° and one of the second coils (designated as coil B) having its center at 90°. Also shown are the turning positions of the loops of these two coils. The flux density is shown only for a 90° sector. The flux density distribution in the remaining three sectors corresponds to the illustrated distribution after shifting and/or mirror inversion along the circumferential direction.
• the flux density generated by coil A is zero outside the outermost conductor loop, at angles beyond 85.5°. Towards smaller angles, it increases stepwise to reach its maximum at the coil center around 0°, where all nine loops of the coil overlap.
• the angular dependence of the flux density of coil B is mirror-symmetric to the distribution of coil B, with the plane of symmetry located at the 45° position.
• the flux density will have the same functional dependence on angle, but will be time dependent, causing EMFs to be induced in both coils. Both flux density and the induced EMFs can be readily modeled by standard FE methods. To a good approximation, the following simplified considerations can be made.
• Figure 14 illustrates the resulting distribution of voltage contributions over the entire angular range from 0° to 360° for the pair of oppositely arranged two first coils 170, 172, assuming that these coils are read out differentially.
• eddy currents are induced in the body.
• the eddy currents damp the electromagnetic field and cause a counter EMF in the nearby conductors. Thereby, the eddy currents will reduce the voltage contribution at that particular angular position.
• the effect of the eddy currents on the total induced voltage in each coil i.e., the sensitivity of the induced voltage to the presence of the conducting body
• the resulting sensitivity distribution just corresponds to the distribution of voltage contributions as illustrated in Fig. 14.
• the sensitivity distribution is sinusoidal over the entire circle from 0° to 360°, i.e., it can be well approximated by a cosine function over the entire circle, deviations from the cosine function being small. It is noted that the integral over the voltage/sensitivity distribution shown in Fig. 14 over the entire circle is zero, i.e., the sensitivity distribution does not exhibit an offset.
• the sensitivity distribution may somewhat deviate from a perfect simple cosine dependence.
• the sensitivity distribution may exhibit step-like features, as apparent from Figs. 13 and 14, due to the presence of discrete loops.
• step-like features can be further reduced by modifying the geometry of the individual loops, e.g., by configuring loops that have a width and/or a radial distance from the longitudinal axis that varies along the circumferential direction. In this manner an improved approximation of a simple cosine dependence can be obtained.
• a second radial position signal along the orthogonal y direction and a second sinusoidal angular signal b sin f can be obtained in the same manner.
• the rotation angle f can be determined. Altogether, two radial position signals along two mutually orthogonal directions x and y as well as the rotation angle f are obtained.
• both the eccentric target geometry and the coil geometry can be optimized such that the convolution of the shape of the eccentric target and the sensitivity distribution matches a true cosine/sine function as well as possible.
• This optimization can be easily implemented because a convolution is a simple multiplication in the frequency domain.
• FIG 16 illustrates a transducer unit according to a second embodiment of the present invention.
• the transducer unit of the second embodiment is very similar to the transducer unit 1 of the first embodiment.
• the outer circumference of second transducer 100’ is covered by an annular, metallic reference target 180 disposed at a fixed radial distance from the first and second coils of the second transducer 100’.
• the coil support of the second transducer has a slightly reduced outer diameter as compared to the coil support of the first transducer.
• transducer unit G of the second embodiment is illustrated in a highly schematic manner in Fig. 17.
• Like components are designated with the same reference numerals as in Fig. 15.
• rotor 300 is illustrated as an internal rotor for simplicity, while it may as well be an external rotor.
• coil 170 of the first transducer and coil 170’ of the second transducer are read out differentially.
• coils 172 and 172’ are read out differentially. Each such pair detects a differential signal that is indicative of the absolute distance between the target and the respective coil of the first transducer.
• a radial position signal that is indicative of the displacement of the rotor along the x direction is obtained.
• a sum symbolized by adder 224
• an output signal that is indicative of the diameter D of the target is obtained.
• the radial position signal can be further corrected for variations of rotor diameter by multiplying the uncorrected radial position signal with a variable gain g to obtain a corrected radial displacement signal x.
• a scaler 225 may receive the diameter value D and output a gain g(D) that depends on D.
• the uncorrected radial position signals are multiplied with this gain g(D ) in multiplier 226 to obtain the corrected position signals.
• the same detection and processing scheme can be applied to the signals obtained from the second coils of the first and second transducers 100, 100’ to derive a (corrected) radial displacement signal y and a second diameter signal.
• the second diameter signal can be used to calibrate the processing circuitry by minimizing differences between the time- averaged diameter signals from the first and second coils.
• An average diameter value as measured by the first and second coils may be used in scaler 225.
• a transducer according to a third embodiment will be described with reference to Figure 18. While the first and second embodiments are designed to interact with an external rotor, the third embodiment is designed for an internal rotor.
• the coils interact radially outwardly with the target.
• the coils can be arranged in the slots from outside and will be held by the hooks of the coil support without any further measures. This is not the case when the transducer is designed to interact with an internal rotor. In this case, specific measures need to be taken to avoid that the coils fall inside and touch the internal rotor. It is therefore proposed to also mount the coils to a coil support from outside, similar to the first and second embodiments. The coils are then filled with resin, and the coil support is turned from the inside until only a thin membrane remains between the coils and the inner circumference of the coil support.
• a coil support 110 that is suited for this kind of mounting of the coils is schematically illustrated in Fig. 18, together with a portion of an internal rotor 300.
• a flexprint 400 that implements two first coils 170, 172 of a single transducer is schematically illustrated in Fig. 19. It is to be understood that conductor portions that cross other conductor portions are arranged in different layers of the flexprint, as it is well known in the art.
• the flexprint is mounted on an electrically insulating annular carrier. Its length corresponds to the inner or outer circumference of the carrier, depending on whether an internal or external rotor is to be monitored. A second, slightly shorter or longer, but otherwise identical flexprint can be disposed on top of this, shifted by 90° along the circumferential direction, in order to implement the second coils.
• each coil generally have different widths along the axial direction. This can readily be taken into account when optimizing coil geometry.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Electromagnetism (AREA)
• Mechanical Engineering (AREA)
• Transmission And Conversion Of Sensor Element Output (AREA)
• Measurement Of Length, Angles, Or The Like Using Electric Or Magnetic Means (AREA)

Priority Applications (3)

Applications Claiming Priority (2)

Publications (1)

Family

ID=61094313

Family Applications (1)

Country Status (5)

Families Citing this family (1)

Citations (8)

Family Cites Families (6)

• 2018
  • 2018-01-30 EP EP18154138.4A patent/EP3517896B1/en active Active
• 2019
  • 2019-01-17 CN CN201980010540.9A patent/CN111656142A/zh active Pending
  • 2019-01-17 US US16/965,386 patent/US20210156717A1/en not_active Abandoned
  • 2019-01-17 JP JP2020562834A patent/JP2021513085A/ja active Pending
  • 2019-01-17 WO PCT/EP2019/051156 patent/WO2019149537A1/en active Application Filing

Patent Citations (8)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events